Publications by authors named "M Spehar"
Substantial advances in livestock traits have been achieved primarily through selection strategies targeting variation in the nuclear genome, with little attention given to mitogenome variation. We analyzed the influence of the mitogenome on milk production traits of Holstein cattle in Croatia based on strategically generated next-generation sequencing data for 109 cows pedigree-linked to 7,115 milk production records (milk, fat, and protein yield) from 3,006 cows (first 5 lactations). Because little is known about the biology of the relationship between mitogenome variation and production traits, our quantitative genetic modeling was complex.
View Article and Find Full Text PDFThe Istrian (IS) and the Pag sheep (PS) are local Croatian breeds which provide significant income for the regional economy and have a cultural and traditional importance for the inhabitants. The aim of this study was to estimate some important population specific genetic parameters in IS (N = 1293) and PS (N = 2637) based on genome wide SNPs. Estimates of linkage disequilibrium effective population size (N) evidenced more genetic variability in PS (N = 838) compared to IS (N = 197), regardless of historical time (both recent and ancient genetic variability).
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- The study focused on understanding the global historical and genetic relationships between Merino sheep and their derived breeds by genotyping 19 populations and analyzing additional data from 23 populations.
- Several statistical tests confirmed that the genetic diversity in Merino breeds is influenced by their geographic origin and local admixture, particularly highlighting the impact of Australian, Rambouillet, and German strains.
- The research identified 106 candidate genes under potential selection, including those related to immune response, growth, morphology, and reproductive traits, indicating the genetic adaptations of Merino sheep to different climates.
The Istrian sheep breed has been subjected to selection for dairy traits for more than two decades. However, a detailed study of some important population-specific parameters such as effective population size (Ne) and connectedness between flocks has never been carried out. The aim of the study was to examine the above parameters in dairy Istrian sheep subjected to a national selection program.
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- The study investigated how the age of ewes at first lambing affects their days in milk (DIM), daily milk yield (DMY), and total milk yield (TMY).
- It found that the age at first lambing significantly influenced DIM but not DMY or TMY, with litter size only affecting TMY.
- The results indicated that delaying mating until the second year is not beneficial for dairy sheep farms, but more research is needed to fully understand the broader implications on profitability.